19 October 2015 - Button switch (momentary) example program and Pi 2B J8 Header

// Program button.c
//
#include <wiringPi.h>
#include <stdio.h>

// One side of the button is placed on GPIO 0
// The other side is on 5V

#define BtnPin 0

int
main(
){
    wiringPiSetup();

    pinMode(BtnPin,INPUT);
   

    for(;;)
    {

            if(0==digitalRead(BtnPin))
                {
                   
                    printf("\nButton is NOT Pressed\n");
                }
            if(1==digitalRead(BtnPin))
            {
                    printf("\nButton is Pressed\n");
            }
    }
       
    return(0);
}
   

DC Motor Control using PWM for Speed Control

In this exercise, we use DC Motor control using PWM for speed control. The electronic driver is called an H-Bridge that will allow the motor to turn either way if hooked up properly. That will be shown in a follow-on Blog entry.

We us a 31162MP H-Driver as hooked up to the Raspberry Pi 2B as shown:
https://www.dropbox.com/s/c0xvxc32x4q75tn/hDrivePi.pptx?dl=0

The specification for the 31162MP H-Driver board is:
https://www.dropbox.com/s/m2cym0tm2e7c2f4/31162mp-Hdriver.pdf?dl=0

Test code using a single speed is shown below. The speed can be set depending on the PWM pulse width of 0-1023. Below a value of about 150, the motor may not turn.
https://www.dropbox.com/s/p5e6wjhjwrra2s2/pwmtest1.c?dl=0

Continuous Temperature Sensor with LED Indicator Program

Continuous Temperature Sensor with LED Indicator Program using linked compile for the functions.

The main program: tempmain.c

https://www.dropbox.com/s/aledcit10fsnssi/tempmain.c?dl=0

GPIO Setup program (function): setupPi.c

https://www.dropbox.com/s/9xy68yat9qdz9ks/setupPi.c?dl=0

LED Off program (function): leds_off.c

https://www.dropbox.com/s/vp331yx87up24q1/leds_off.c?dl=0

Read Temperature Sensor program (function): readTemp.c

https://www.dropbox.com/s/hdp7xa2pph2lqkt/readTemp.c?dl=0

Turn on LED Corresponding to Temperature (I used 3 temperature ranges): led_temp_on.c

https://www.dropbox.com/s/bw6s3n70g44v33x/led_temp_on.c?dl=0

To compile:

gcc tempmain.c setupPi.c leds_off.c readtemp.c led_temp_on.c -lwiringPi

It'll keep running forever.

Single Pass Example Temperature Sensor with LED Indicator Program

SINGLE PASS Example Temperature Sensor with LED Indicator Program using linked compile for the functions.

The main program: tempmainEx.c

https://www.dropbox.com/s/jpksjn9iz7h9eua/tempmainEx.c?dl=0

GPIO Setup program (function): setupPiEx.c

https://www.dropbox.com/s/bs4jdagb6rz9cco/setupPiEx.c?dl=0

LED Off program (function): leds_offEx.c

https://www.dropbox.com/s/h93vi8flb30vlqi/leds_offEx.c?dl=0

Read Temperature Sensor program (function): readTempEx.c

https://www.dropbox.com/s/h9e6hnzj4mz0hku/readTempEx.c?dl=0

Turn on LED Corresponding to Temperature (I used 3 temperature ranges): led_temp_onEx.c

https://www.dropbox.com/s/hztso66dyvmrhek/led_temp_onEx.c?dl=0

To compile:

gcc tempmainEx.c setupPiEx.c leds_offEx.c readtempEx.c led_temp_onEx.c -lwiringPi

You'll see on the display when certain entries and exits to and from functions occur.